Rotary window cutting mechanism



May 4, 1954 Filed April 28, 19

A. NOVICK ROTARY WINDOW CUTTING MECHANISM 4 Sheets-Sheet l Abra/7am Nor/bk BY AT TOR/YE Y5 May 4, 1954 A. NOVICK ROTARY wmoow CUTTING MECHANISM 4 Sheets-Sheet 2 Filed April 28, 1950 May 4, 1954 A. NOVICK ROTARY WINDOW CUTTING MECHANISM 4 Sheets-Sheet 4 Filed April 28, 1950 m R w wk Wu NK R EV 0 V0 T mN ,m m M a m 0 A M Y B Patented May 4, 1954 UNITED STATES PATENT OFFICE Abraham Novick, Flushing, N. Y., assignor to F. L. Smithe Machine (30., 110., New York, N. Y., a

corporation'of New York Application April 28, 1950, Serial No. 158,830

4 Claims. 1

This invention relates to rotary die mechanism designed for cutting openings in paper sheets or webs and particularly openings which will afterward appear as the windows of window envelopes. The invention is equally applicable whether the dieing operation is to be performed upon previously cut envelope blanks or upon continuous webs which are subsequently to be made into envelope blanks. It is to be understood,

however, that the invention is not restricted to operation upon envelope blanks or upon webs which are destined to form envelope blanks, but that it is adapted also for other uses.

To effect a cutting action between the rotary elements, it is necessary for their cutting edges to overlap at the cutting operation, and hence for the cutting edges of one or both of them to project beyond. the circular pitch line between the rolls. When both the dies are made to proiect uniformly and equally beyond the pitch line each has projecting parts which. travel faster than the pitch line speed. .It is necessary then, in order to prevent interference between the rapidly traveling overlapping edges, to allow so much backlash in the gearing for driving the dies that a consistently clean cutting action cannot be obtained. Even with the allowance of such backlash, however, the dies wear away rapidly. The difficulty is especially pronounced with respect to the cutting edges which extend parallel to the roller axes or which include substantial axial components, because a greater overlap is required along these edges than along edges which are designed to produce circumferentially extending cuts.

The present invention. has for its primary object to provide an improved die combination in which the parts are adapted to .cut cleanly throughout, and in which no allowance of backlash is required in order to overcome interference. The parts are so constructed and arranged for mutual cooperation that they exert relatively little rubbing and wearing action upon one another.

A. further object is to provide for die reshaping and resharpening as required.

Other objects and advantages will hereinafter appear.

In the drawing forming part of this specification:

Figure 1 is a fragmentary view in side elevation, diagrammatically showing a portion of an illustrative machine which is designed to act upon separate envelope blanks and which embodies features cf the invention;

Figure 2 is a fragmentary diagrammatic view of another machine embodying features of the invention, the mechanism of Figure 2 differing from that of Figure l in the fact that it is designed toact upon the webs, rather than upon separate envelope blanks;

Figure is a fragmentary view in elevation of a die set employed in Figure 1, together with the supportin and operating mechanism therefor;

Figure 4 is a fragmentary plan View showing an envelope blank in cutting position with relation to the lower die, and the feeding instrumentalities located at that point below the path of blank travel;

Figure 5 is a fragmentary sectional view taken upon the line 55 of Figure 3, looking in the direction of the arrows, the view being upon a substantially larger scale than Figure 3 and showing the dies in different positions; and

Figures v6, '7, 8 and 9 are fragmentary, sectional views illustrating the coaction of the die at successive stages of the cutting operation.

An illustrative machine embodying the invention and adapted to act upon envelope blanks is shown in Figures 1 and 3 to 9, inclusive. Envelope blanks, like the blank l of Figure 4, are fed individually from a stack onto a conventional pin conveyor lit by any suitable mechanism such, for example, as the mechanism disclosed in United States Patent No. 2,315,546 granted to me on April 6, 1.943. The blanks are advanced continuously through die mechanism by which the window openings 3 (see Figure 4) are out.

The blanks are advanced, bottom flaps first, by the chain conveyor t8, the chains being provided with pins H which engage in the angles formed at the. junctions of the side naps with the sealing flaps. The pins serve to perfect the timing and the alignment of the blanks. At the delivery end the chains run upon sprockets E9. Each blank is thrust forward across a table 5 and onto a feed roll "it where it is engaged and driven forward by cooperating feed segments i l. The blanks are further advanced across a table i5, whence they are drawn forward by a lower feed roller '36 and two upper feed rollers i! cooperating therewith. The blanks are advanced by the feed rolls it and i? across a table it to rotary die mechanism it. The blanks are then fed away from the rotary die mechanism it by opposed feed rollers is?) and me. It is the rotary die mechanism it with which the invention is.

really concerned.

Upright frame members 86 and 84 supported upon a base 82 provide bearings for upper and lower parallel shafts 83 and 84. The upper and lower shafts have bearers 85 afiixed to them which are adapted to engage one another at all times. Between the bearers, the lower shaft 84 has metallic feed rolls 86 secured to it, while the upper shaft 83 has correspondingly located, rubber tired feed rolls 81 secured to it. Between the feed rolls 86, female die mechanism 88 is secured upon the shaft 84, and between the feed rolls 81, male die mechanism 89 is secured upon the shaft 83.

The male die 96 is seated in a recess 9! of a block 92, being held in place by countersunk headed screws 93. The block 92 is formed with a substantially semi-cylindrical groove which fits the shaft 63 and is opposed by a similarly grooved block 94. Clamping screws 95 are passed through flanges of the block 94 and threaded into flanges of the block 92 to secure the blocks 92 and 94 firmly in place upon the shaft 83.

The female die 96 is mounted upon a block 9'! having a substantially semi-cylindrical groove formed in it which fits the shaft 84. A block 98 having a similar groove is opposed to the block 9'! and is secured to it by clamping screws 99 which may be turned to cause the blocks 91 and 98 to grip the shaft firmly between them.

It is important that the leading cutting edge of the female die travel more rapidly than the corresponding edge of the male die so that these edges may cut the blank as they move into overlapping relation, as illustrated in Figure 6, and the leading edge of the female die may then move forward away from the leading edge of the male die to prevent these edges from clashing or rubbing as their paths again cross (see Figure 7). It is similarly desirable that the trailing cutting edge of the male die move faster than the trailing cutting edge of the female die so that these edges may cooperate to cut the blank as they move into overlapping relation, as illustrated in Figure 8, but will then be caused to separate by the faster travel of the trailing cutting edge of the male die to prevent these edges from clashing or rubbing as their paths again cross in the position illustrated in Figure 9.

In order to bring about this kind of operation, it is necessary that the leading cutting edge of the female die be made to protrude beyond the pitch line of the gears (to be later described) by which the shafts 83 and 84 are caused to travel at equal rotary speeds and that the trailing cutting edge of the male die be also caused to protrude beyond the pitch line. In other words, the eifective radii of the leading edge of the female die and of the trailing edge of the male die are each greater than half the distance between the axes of the shafts 83 and 84.

In order to effect cutting, there must necessarily be overlapping of the male and female dies at every point and this necessarily means that at each point at which cutting occurs, one or both of the dies must protrude beyond the pitch line. If the leading cutting edge of the female die is made to protrude only to the minimum extent necessary for cutting, while the leading cutting edge of the male die is made to coincide with the pitch line, the difference of speed of these two edges can only be equal to 21mm, where n is the number of revolutions per second, and a: is the amount of overlap essential for cutting.

If, however, the male die is made to fall short of the pitch line by, say, a:/2, and the corresponding portion of the female die is extended to maintain the same overlap, :c, as before, the protrusion of the female die will amount to 3x/2 and the difference of radii will be 2m. The difference of speeds now becomes 41mm or twice as great as before, a result which is somewhat surprising in view of the fact that the protrusion of the female die was increased only fifty percent.

To make the analysis more general, let the out back of the leading edge of the male die be mm. Then the protrusion of the female die must be :r(m+1) in order to provide the overlap, :c. The difference of radii becomes :r(2m+1) and the difference of speed 21rna:(2m+1). This principle is utilized to make the leading edge of the male die travel substantially slower than the leading edge or the associated pitch line portion of the female die and to make the trailing edge of the female die travel substantially slower than the trailing edge or the associated pitch line portion of the male die.

Although the leading edge of the female die 96 is made protruding and the trailing edge receding, as the die is mounted in the machine, the die is desirably made symmetrical in construction for economy of manufacture, and the desired protrusion and recession are brought about by mounting the die non-symmetrically upon the block 91. This will be made clearer by reference to Figure 5.

In Figure 5 it will be observed that the die 96 has a fiat inner face I00 and that the block 9? has a flat supporting face IOI that extends along a chord of the pitch circle. If the die were supported upon the block 91 with its longitudinal median plane in coincidence with the radial plane l 532, the arcuate outer face of the die would coincide throughout with the circumference of the pitch circle, the radial plane I02 being the perpendicular bisector of the chord along which the face EDI extends.

The die, however, is mounted with its longitudinal central plane substantially to the right of the plane I02, as seen in Figure 5, so as to cause the leading cutting edge to protrude in the illustrative construction three sixty-fourths of an inch beyond the pitch circle and the trailing cutting edge to fall three sixty-fourths of an inch short of the pitch circle.

The block 91 is formed with an undercut rib I63 against which the leading face of the die is placed. The die is secured in position by means of a clamp bar I04 and screws I05. The clamping bar is formed with a recess H38 so that it bears only at one margin against a face of the block 9'! and only at the opposite margin against the trailing face of the die 96. The screws are passed freely through the bar I04 and threaded into the block 91.

The male die 90, on the other hand, is mounted with its longitudinal median plane radially disposed. The leading edge of the illustrative male die is made to fall short of the pitch circle by one sixty-fourth of an inch, while the trailing edge of the male die is made to protrude beyond the pitch circle by five sixty-fourths of an inch (Fig. 5). It will thus be seen that an overlap of one thirty-second of an inch is provided at the leading cutting edges of the dies and at the trailing cutting edges.

The protrusion of the trailing edge of the male die is however greater than that of the leading edge of the female die and, since the overlap is the same at the leading and trailing edges, the recession of the trailing edge of the female die is greater than that of: the leadingedge of the male die. This is a desired relationship: because there is a greater need for'disparityof' speed between the trailing edges of the dies-than between the leading edges of the dies. Theprincipal reason for the disparity is, however, that it follows logically from the symmetrical construction of the female die 96 and the non-symmetrical mounting of that die.

While the externalfaceof. thefemale die is arcuate this is not true of the exterior of the-male die. The male die- 90 has four external plane faces itl', Hi8, itt, it'll". The formation of the die with these planefaces results a somewhat irregular amount of overlap between theleading and trailing cutting edges ofthe die. Thisis not disadvantageous, however; because the maximum overlap is required only atthe leading and trailing edges which run parallel to the roll axes.

The fact that the plane faces I01 and I Iii are provided contributes importantly to the convenient and practical resharpening and reconditioning of the die. Two, slots III and. H2 are provided which extend parallel to the leading andtrailing edges and. which penetrate the die it to a considerable depth. The slot Hit is dis posed between the faces It]; and its while the slot H2 is disposed between the faces I69 and Iii). When it is desired to resharpen and reshape the leading edge-of the die'90, a wedge may be driven at intervals into the slot III so as to displace the edge II3 outward by a slight but important amount. The edge is then reground and the face I! is smoothed out so as to relocate the edge H3 precisely in its original position. A similar procedure is followed in resharpening and reshaping the trailing edge H 5.

Both dies are desirably undercut adjacent their leading and trailing edges, as shown. This is particularly important in the case of the leading edge of the male die and the trailing edge of the female die, for avoiding interference and affording easy and comfortable clearance.

The male die 90 is formed near its leading edge with a series of suction passages IZI which communicate through passages I22 and I23 with a longitudinal bore I24 of the block 92. The pas-- sages I23 cross the bore I24 but are plugged to the right of the bore by plugs I25 as seen in Fig. 5. The bore I24 communicates through suitable valve mechanism (not shown) with a source of suction (not shown). At the time when the die is in cutting position the suction is applied in the passages I2I to secure to the die the piece which is cut from the blank to form the window opening. At a subsequent point in the cycle the suction is broken in the passages I2I so that the cut-out piece can be removed from the die and disposed of in an orderly manner.

The mechanism for driving the shafts 83 and 84 is designed to eliminate all back lash. A drive gear E26 drives a gear I21 which is fast upon the shaft 84. The gear IZ'I drives an equal gear hi8 which is fast upon the shaft 83. The shaft 83 has fast upon it a gear I29 which is in mesh with an equal gear I30, the latter gear being mounted with capacity for rotative adjustment upon the shaft 84.

The gear I36 carries a lug I3I through which a screw I32 is threaded. The screw bears at one end against an arm I33 which is fast upon the shaft 34. When the screw is turned in a direction to press it toward the arm I33 the block I3I is caused to recede from the arm and hence to adjust the gear I30. Since the gear I30, is in mesh; however, with. the gear. b29 the capacity for adjustmentis: a limited one, and the turning of the screw is persisted; in only to. the point of eliminating all back-lash from the gearing. When this has been achieved the screw I32 is fixed in its adjusted position by the tightening of a lock nut I34.

The machine of Fig. 2 employs a die uniti 79a which may be in all respects a. duplicate of the die unit 19 shown in, and described in connection with, Figs. 1 and 3 to9 inclusive. In this form of embodiment, however, a work web I40 is fed from a reel MI by means-ofpull rollsMZ and M3. The web is advanced through the die unit 39a and is further fed away from the die unit by opposed feed rollers I44 and I45. After passing the latter rollers the web may be rewound or may be cut into lengths or treated in any other manner suitable to the purpose which it is de-- signed to serve.

I have described what I believe to be the embodiments of my invention. I donot wish, however, to be confined to the embodiments shown but what I desire tocover by Letters Pat ent is set forth in the appended claims.

I claim:

1. In rotary cutting mechanism the combination with'two rolls having their axes parallel, of cooperating male andfemale-windowcutting dies carried by the respective rolls; said dies having cooperating cutting edges at their leading and trailing ends that extend in part at least axially of the rolls, the cutting edges of said dies being of such effective radii that they are caused to overlap slightly in all cutting positions, the cutting edge of the male die at the leading end falling short of the pitch line of its supporting roll and the cutting edge of the female die at the leading end extending beyond the pitch line of its supporting roll by a corresponding amount plus the overlap; and the cutting edge of the female die at the trailing end falling short of the pitch line of its supporting roll by an amount in excess of the overlap and the cutting edge of the male die at the trailing end extending beyond the pitch line by a corresponding amount plus the overlap, both the male die and the female die being undercut adjacent the leading and trailing cutting edges thereof to avoid interference and to assure comfortable clearances.

2. In rotary cutting mechanism the combination with two rolls having their axes parallel, of cooperating male and female window cutting dies carried by the respective rolls, said dies having cooperating cutting edges at their leading and trailing ends that extend, in part at least, axially of the rolls, the cutting edges of said dies being of such effective radii that they are caused to overlap slightly in all cutting positions, the cutting edge of the male die at the leading end falling short of the pitch line of its supporting roll by a substantial amount so that it will travel substantially more slowly than die parts which reach to or beyond said pitch line, and the cutting edge of the female die at the leading end extending beyond the pitch line of its supporting roll by a corresponding amount plus the overlap; and the cutting edge of the female die at the trailing end falling short of the pitch line of its supporting roll by an amount substantially greater than the amount by which the cutting edge of the male die at the leading end falls short of the pitch line, so that the cutting edge of the female die at the trailing end will travel substantially more slowly than die parts which reach to or beyond said itch line, and the cutting edge of the male die at the trailing end extending beyond the pitch line by a corresponding amount plus the overlap, both the male die and the female die being undercut adjacent the leading and trailing cutting edges thereof to avoid interference and to assure comfortable clearances.

3. In rotary cutting mechanism the combination with two rolls having their axes parallel, of cooperating male and female Window cutting dies carried by the respective rolls, said dies having cooperating cutting edges at their leading and trailing ends that extend in part at least axially of the rolls, the cutting edges of said dies being of such effective radii that they are caused to overlap slightly in all cutting positions, and the female die having an arcuate outer face and means mounting the female die unsymmetrieally upon its supporting roll to cause the leading and trailing cutting edges respectively to protrude beyond and fall short of the pitch line by substantially equal amounts, each in excess of the overlap, both the male die and the female die being undercut adjacent the leading and trai1- ing cutting edges thereof to avoid interference and to assure comfortable clearances.

4. In rotary cutting mechanism the combination with two rolls having their axes parallel, of cooperating male and female window cutting dies carried by the respective rolls, said dies having cooperating cutting edges at their leading and trailing ends that extend in part at least axially of the rolls, the cutting edges of said dies being of such effective radii that they are caused to overlap slightly in all cutting positions, and the female die having a fiat supporting face and an arcuate outer face and being of symmetrical construction, and means mounting the female die unsymmetrically upon its supporting roll to cause the leading and trailing cutting edges respectively to protrude beyond and fall short of the pitch line by substantially equal amounts, each in excess of the overlap, the male die and the female die being undercut adjacent the leading and trailing cutting edges thereof to avoid interference and to assure comfortable clearances.

References Cited in the file of this patent UNITED STATES PATENTS Number Number 

